As part of their day-to-day business, many organizations require an enterprise network, a private network with lease lines, dedicated channels, and network connectivity devices, such as routers, switches, and bridges. These components, collectively known as the network's “infrastructure,” are very expensive and require a staff of information technology personnel to maintain them. This maintenance requirement is burdensome on many organizations whose main business is not related to the data processing industry (e.g., a clothing manufacturer) because they are not well suited to handle such data processing needs.
Another drawback to enterprise networks is that they are geographically restrictive. The term “geographically restrictive” refers to the requirement that if a user is not physically located such that they can plug their device directly into the enterprise network, the user cannot typically utilize it. To alleviate the problem of geographic restrictiveness, virtual private networks have been developed.
In a virtual private network (VPN), a remote device or network connected to the Internet may connect to the enterprise network through a firewall. This allows the remote device to access resources on the enterprise network even though it may not be located near any component of the enterprise network. For example, FIG. 1 depicts a VPN 100, where enterprise network 102 is connected to the Internet 104 via firewall 106. By using VPN 100, a remote device D1 108 may communicate with enterprise network 102 via Internet 104 and firewall 106. Thus, D1 108 may be plugged into an Internet portal virtually anywhere within the world and make use of the resources on enterprise network 102.
To perform this functionality, D1 108 utilizes a technique known as tunneling to ensure that the communication between itself and enterprise network 102 is secure in that it cannot be viewed by an interloper. “Tunneling” refers to encapsulating one packet inside another when packets are transferred between two end points (e.g., D1 108 and VPN software 109 running on firewall 106). The packets may be encrypted at their origin and decrypted at their destination. For example, FIG. 2A depicts a packet 200 with a source Internet protocol (IP) address 202, a destination IP address 204, and data 206. It should be appreciated that packet 200 contains other information not depicted, such as the source and destination port. As shown in FIG. 2B, the tunneling technique forms a new packet 208 out of packet 200 by encrypting it and adding both a new source IP address 210 and a new destination IP address 212. In this manner, the contents of the original packet (i.e., 202, 204, and 206) are not visible to any entity other than the destination. Referring back to FIG. 1, by using tunneling, remote device D1 108 may communicate and utilize the resources of the enterprise network 102 in a secure manner.
Although VPNs alleviate the problem of geographic restrictiveness, they impose significant processing overhead when two remote devices communicate. For example, if remote device D1 108 wants to communicate with remote device D2 110, D1 sends a packet using tunneling to VPN software 109, where the packet is decrypted and then transferred to the enterprise network 102. Then, the enterprise network 102 sends the packet to VPN software 109, where it is encrypted again and transferred to D2. Given this processing overhead, it is burdensome for two remote devices to communicate in a VPN environment.
Each address used by the VPN contains implicit information as to the delivery scheme (e.g., broadcast, mutlicast, or unicast) to use. For example, the well-known “224.x.x.x” IP range relates to multicast addresses. Some addresses are even bound to a designated interface. For example, the “127.x.x.x” IP range is bound to a loopback interface on the Internet. Forcing an address to be associated with a delivery method unnecessarily restricts addressing schema. In the example mentioned above, a destination address in the “127.x.x.x” range always refers to the loopback interface and can never be changed. Because of this limitation, it is extremely hard to experiment with new or different addressing schemes on a large scale. For example, IPv6, a new addressing scheme has yet to be fully deployed on the Internet because of the different addressing scheme. IPv6 is described in greater detail in “ftp://ftp.isi.edu/in-notes/rfc2373.txt”.
Therefore, it is desirable to provide addressing functionality that easily integrates and supports existing infrastructure services while at the same time allows for multiple delivery schemes.